Polymeric blends

ABSTRACT

Polymer blends of at least one polar polymer are prepared by admixture with a poly(vinyl alcohol) and a (meth)acrylate copolymer also containing vinyl amide and/or unsaturated acid units. The ternary compositions have attractive processing and performance properties.

This application is a continuation-in-part of U.S. application Ser. No.08/83,957, filed Jun. 25, 1993, which in turn is a continuation-in-partof U.S. application Ser. No. 929,878, filed Aug. 12, 1992, nowabandoned.

This invention relates to melt-processable thermoplastic combinations ofpolymers containing a high percentage of vinyl alcohol units blendedwith certain copolymers of alkyl methacrylates and/or acrylates withunsaturated organic acids, such as methacrylic add, and/or vinyl amidestructures, such as N-vinyl pyrrolidone group, which composites are thenblended (or the three polymers simultaneously blended) with one or morepolar polymers, such as polyesters, such as poly(ethyleneterephthalate), poly(vinyl chloride), polyurethanes, such asthermoplastic polyurethanes, polyamides, polycarbonates, ethylene-vinylalcohol co- and terpolymers, polyglutarimides, polymers and copolymersof methyl methacrylate, naturally occurring polymers such as starch,chitin, chitosan, lignin or cellulose and the like. Such blends may beprocessed by conventional plastics technology to form sheet, extruded orblown film, molded articles, and the like, which exhibit a usefulbalance of barrier and strength properties, such as good resistance topermeation of gases, low moisture absorptivity, and toughness/modulusbalance adequate for packaging uses.

Of all the synthetic polymers considered as materials with useful gaspermeation properties, such as resistance to passage of oxygen, carbondioxide, water, and the like, poly(vinyl alcohol) (PVOH), which is apolymer made up of units of the structure ##STR1## and generallyprepared by the total or almost total hydrolysis of homopolymers ofvinyl acetate or related vinyl esters, the starting polymer made up ofunits of the structure ##STR2## where R is alkyl, that is, from one toeight carbon atoms, preferably methyl, ranks as the most impervious tothe passage of small molecules. PVOH derives this property from the highcohesive energy density and polarity of the hydroxyl groups. Thepresence of the network of hydroxyl groups has the concomitant effect ofrendering the polymer (PVOH) impermeable to gases, but sensitive tomoisture. The strong intermolecular interaction resulting from the highpolarity of the --OH functional group gives rise to a meltingtemperature in the vicinity of the degradation temperature of PVOH.Consequently, melting is accompanied by degradation. The degradation isso severe that PVOH by itself cannot either be melt extruded orinjection molded. Co-polymers having a low mol percentage of ethylene,such as from about 5 to about 25 mol percent, are similar to poly(vinylalcohol) in that they cannot be melt-processed into film without the aidof plasticizers.

In U.S. patent application 07/781,715, filed Oct. 22, 1991 now U.S. Pat.No. 5,189,097, now also European Patent Application 91-311265, filedDec. 4, 1991, which has some of the same inventors as the presentapplication, are disclosed additive polymers useful in allowing meltprocessing of the poly(vinyl alcohol) materials discussed above withoutsignificant alteration of their physical and barrier properties. Theseadditive polymers are copolymers of lower alkyl methacrylates oracrylates with a variety of nitrogenous monomers, especially thosebearing amide groups, and most especially N-vinylpyrrolidone. Further isdisclosed as more useful additives terpolymers containing lower alkylmethacrylates or acrylates, the same nitrogenous co-monomers, andcopolymerized unsaturated carboxylic acids, such as methacrylic acid. Itis further disclosed that these latter terpolymers form segmentedcopolymers on combining with the poly(vinyl alcohol) matrix polymersunder certain processing conditions. These composites, on the basis ofelectron microscopy, contain the copolymer or terpolymer additivesdispersed within the poly(vinyl alcohol) matrix. These additives alsodiminish the barrier properties of the composites relative to theunmodified poly(vinyl alcohol).

In a patent application in the U.S. Ser. No. 872,478, filed on Apr. 23,1992 now abandoned, also with some of the same inventors as the presentapplication, is disclosed that copolymers of lower alkyl methacrylatesand/or acrylates with unsaturated carboxylic acids, such as copolymersof methyl methacrylate with methacrylic acid, are also useful for thesame purposes. It is further disclosed that the composites so formed maybe segmented copolymers under certain processing conditions. Thesecomposites, on the basis of electron microscopy, will also contain thecopolymer or terpolymer additives dispersed within the poly(vinylalcohol) matrix.

What has been discovered in the present invention is that certain ofthese composites of poly(vinyl alcohol), or copolymers which contain atleast 50 mol % of ##STR3## units, with lower alkyl methacrylate oracrylate copolymers with at least one of copolymerized add or amide,especially cyclic amide, functionality, when melt-blended withstructural polar polymers, produce blends of excellent physical, opticaland barrier properties.

In the applications noted above, it had been found that a polymericcomposite comprising from about 40 to about 95 parts, of a first polymercontaining at least 50 mol % of units, preferably at least 90 mol %, ofthe structure ##STR4## and optionally units of the structure

    --CH.sub.2 --CHR--

where R is H or CH₃, and from 5 to about 60 parts by weight of a secondpolymer containing at least about 70 parts of units derived from atleast one lower alkyl methacrylate or acrylate, preferably methylmethacrylate, and at least one of either up to about 25 parts of unitsderived from a vinyl or vinylidene monomer containing an amide group,preferably a cyclic amide group of units of the structure ##STR5## wheren is 2, 3, 4, or 5, preferably units derived from N-vinyl pyrrolidone,or up to about 25 parts of units derived from an unsaturated carboxylicacid or anhydride, preferably methacrylic acid, may be melt-processed,such as by extrusion, into useful objects such as sheet, film, andfiber. It had further been found that combination of the two polymersnoted above by melt-mixing will form a segmented melt-processablepolymer wherein the two polymers are chemically combined to form a graftcopolymer. Lower levels, down to 2 parts, of the additive in thecomposite may be used when the additive polymer is free from amidefunctionality or when the composite contains poly(vinyl alcohol) whichhas been washed or has been neutralized with acid such as phosphoricacid to remove residual sodium acetate, as taught in U.S. Pat. No.3,425,979. It is preferred to utilize the composites from a secondpolymer which does not contain amide or cyclic amide groups for ease ofpreparation and lower cost of the acrylic additive. Such composites maybe substituted directly for the composites exemplied herein.

It is now been found that these composites may be blended, preferably inthe melt, with polar polymers, to give a melt-processable blend whichmay be processed into useful sheet, film, or molded objects. In thesense that processing of the polar polymer is improved, these compositesmay be considered "processing aids". Polar polymers may be described aspolymers which contain functionality other than carbon and hydrogen, andinclude poly(vinyl halides), such as poly(vinyl chloride) (PVC), poly(vinyl esters), such as poly(vinyl acetate), poly(meth)acrylic esters,polyglutarimides, polymers containing (meth)acrylonitrile, such asstyrene/acrylonitrile copolymers or acrylonitrile/butadiene/styrenecopolymers (ABS), polyesters, such as poly(alkylene terephthalates),polyamides, ethylene-vinyl alcohol co- and terpolymers, of less than 50mol % vinyl alcohol units, ethylene-carbon monoxide copolymers,polycarbonates, poly(alkylene oxides), such as poly (propylene oxide) orpoly(ethylene oxide), phenoxy resins, such as those formed by thereaction of epichlorohydrin and a bisphenol, and the like. The inventionfurther applies to polar polymers which are of natural origin ormodified from polymers of natural origin, such as starch, lignin,chitin, chitosan, cellulose, or chemically modified cellulose, such asesters such as cellulose acetate, cellulose acetate-propionate,cellulose acetate-butyrate, or ethers such as methyl cellulose. Many ofthese polymers are extremely difficult to process, and may be describedas melt-intractable. The ratio of polar polymers to the composites maybe from about 10:95 to about 5:90, preferably for thermoplastic polarpolymers from about 60:95 to about 5:40, and more preferably from about80:95 to about 5:20. Particularly useful polar polymers are aliphaticpolyamides formed from lactams, such as polycaprolactam,polyundecanolactam, and polydodecanolactam, the polycarbonate formedfrom bisphenol A, poly(ethylene terephthalate), and elastomericpolyurethanes, such as those with polyether or polyester-polyolsegments.

Our invention is thus a polymeric blend comprising:

(a) from about 80 to about 95 parts of at least one polar polymerselected from the group consisting of poly(vinyl chloride), apolycarbonate, a polyglutarimide, a polymer of methyl methacrylate, apolyamide, a polyester, or a polymer containing units derived fromstyrene and acrylonitrile;

(b) from about 5 to about 20 parts of a polymeric composite of:

i) from about 60 to about 95 parts by weight of a first polymercontaining at least 50 mol % of units of the structure ##STR6## ii) fromabout 5 to about 40 parts by weight of a second polymer containing atleast about 70 parts of units derived from at least one of a lower alkylmethacrylate or acrylate, and at least one of either up to about 25parts of units derived from a vinyl or vinylidene monomer containing anamide group or up to about 25 parts of units derived from an unsaturatedcarboxylic acid or anhydride, the composite containing the secondpolymer dispersed in a continuous phase of the first polymer.

The invention further comprises a polymeric blend comprising:

(a) from about 10 to about 95 parts of at least one polar polymer;

(b) from about 5 to about 90 parts of a polymeric composite of:

i) from about 40 to about 95 parts by weight of a first polymercontaining at least 50 mol % of units of the structure ##STR7## ii) fromabout 5 to about 60 parts by weight of a second polymer containing atleast about 70 parts of units derived from a lower alkyl methacrylate oracrylate, and at least one of either up to about 25 parts of unitsderived from a vinyl or vinylidene monomer containing an amide group orup to about 25 parts of units derived from an unsaturated carboxylicacid or anhydride, wherein the polar polymer is a natural andmelt-intractable polymer, such as starch, chitin, chitosan, lignin orcellulose. Again, the components (a), (b)(i), and (b)(ii) may becombined essentially simultaneously.

The invention further comprises a polymeric blend comprising:

(a) from about 25 to about 95 parts of at least one polar polymer;

(b) from about 5 to about 75 parts of a polymeric composite of:

i) from about 40 to about 95 parts by weight of a first polymercontaining at least 50 mol % of units of the structure ##STR8## ii) fromabout 5 to about 60 parts by weight of a second polymer containing atleast about 70 parts of units derived from at least one of a lower alkylmethacrylate or acrylate, and at least one of either up to about 25parts of units derived from a vinyl or vinylidene monomer containing anamide group or up to about 25 parts of units derived from an unsaturatedcarboxylic acid or anhydride, wherein the polar polymer is apolyurethane, such as an elastomeric polyurethane, a phenoxy resin, anethylene/carbon monoxide copolymer, a modified cellulosic, such as acellulose ester, or a poly(alkylene oxide), the composite containing thesecond polymer dispersed in a continuous phase of the first polymer.

The invention further comprises all such above-described blends whereinthe polymeric composite comprises:

(a) from about 60 to about 95 parts by weight of a first polymercontaining at least 50 mole % of units of the structure; ##STR9## ii)from about 5 to about 40 parts by weight of a second polymer containingat least about 75 parts of units derived from methyl methacrylate, andat least one of either up to about 25 parts of units derived fromN-vinyl pyrrolidone or up to about 25 parts of units derived frommethacrylic acid.

Such blends may be in the form of an extruded film, extruded sheet,extruded fiber, or injection-molded article. Such blends may be preparedby methods wherein components (a), (b)(i), and (b)(ii) are combinedessentially simultaneously.

In the claims and description, the parts of polar polymer and ofcomposite total 100 parts, and other materials may be present as long asthe polar polymer and composite are within the specified ratios.Similarly, the parts by weight of the vinyl alcohol polymer and theacrylic co- or terpolymer in the composite total 100 parts, and othermaterials may be present as long as the vinyl alcohol and acrylicpolymers are within the specified ratios.

The composite may contain a blend of high and low molecular weight vinylalcohol polymers. The composite may further contain glycerol or otherplasticizer in small amounts. The composite may further contain impactmodifiers known to the art, such as multistage polymers based on apoly(acrylate) first stage or a polybutadiene first stage and amethacrylate or styrene second stage, which may be present as a shell orin separate domains within the core. The composite contains the secondpolymer dispersed in a continuous phase of the first polymer, as can bedetermined by electron microscopy. Either stage may containadd-functional groups.

The blends may be prepared by dry-blending the components andmelt-processing in an extruder or thermal mixer to form pellets, whichare then re-processed into the desired object, or the dry blend may bedirectly melt-processed into the final article. The blend may containmore than one polar polymer. The blend may further contain pigments,dyes, thermal stabilizers, antioxidants, lubricants, fillers, and thelike. The blend may further be prepared by admixing the additive polymerin emulsion form, when an emulsion polymerization is a feasible way toprepare the additive polymer, with the poly(vinyl alcohol) in solidform, and then processing directly with water removal such as byextrusion in a vented extruder, or by drying the powder blend undervacuum, and then blending with the matrix polymer. The blend may furtherbe prepared by admixing the additive polymer in emulsion form, when suchis feasible to prepare the additive polymer, with the poly(vinylalcohol) and the matrix polymer in solid form, and then processingdirectly with water removal such as by extrusion in a vented extruder,or by drying the powder blend under vacuum, to form the blend.

The blend may further be prepared by admixing the additive polymer inemulsion form, when an emulsion polymerization is a feasible way toprepare the additive polymer, with the poly(vinyl alcohol) in solidform, and then processing directly with water removal such as byextrusion in a vented extruder, or by drying the powder blend undervacuum, and then blending with the matrix polymer. The blend may furtherbe prepared by admixing the additive polymer in emulsion form, when suchis feasible to prepare the additive polymer, with the poly(vinylalcohol) and the matrix polymer in solid form, and then processingdirectly with water removal such as by extrusion in a vented extruder,or by drying the powder blend under vacuum, to form the blend.

By use of the term "composite" in the specifications and claims, thereis meant no restriction that the poly(vinyl alcohol) component and theacrylic copolymer additive component must be blended together prior toadmixture with the polar polymer. Indeed, one particular aspect of theinvention could be described equally well as a polymeric blendcomprising:

(a) from about 25 to about 95 parts of at least one polar polymer;

b) from about 2 to about 71.25 parts of a first polymer containing atleast 50 mol % of units of the structure ##STR10## c) from about 0.25 toabout 45 parts by weight of a second polymer containing at least about70 parts of units derived from a lower alkyl methacrylate or acrylate,and at least one of either up to about 25 parts of units derived from avinyl or vinylidene monomer containing an amide group or up to about 25parts of units derived from an unsaturated carboxylic acid or anhydride.

Thus, the invention is meant to describe those blends where the threecomponents are combined together all at one time, i.e., essentiallysimultaneously, as well as when the second (additive) polymer and thefirst polymer containing poly(vinyl alcohol) are combined first and thenblended with the matrix polymer.

The resulting objects may be especially useful in packaging, such asfilm, sheet, bottles, etc., where improved barrier properties aredesirable, since the invention offers a way to combine poly(vinylalcohol), with outstanding barrier properties, into polar polymers by aneconomically attractive means. Such uses may include bottles forbeverages, film packaging for food, and the like. The blends may also beuseful in a variety of molded or thermoformed objects, where acombination of improved modulus and good processing is required. Suchobjects include toys, electrical equipment housing, and the like.

Melt blends of polyamides with the polymeric composites described hereinmay be fabricated into film, film tubes, toys, gears, packing, shafts,curtain sliders, door rollers, household containers, and the like.Blends of the composites with a compatible, flexible elastomericmaterial may be used as compositions for contact with water and a rigidsubstrates, as for example in improved wiper blades.

The composite (or the two separate components of the composite) may beblended with polymers which are environmentally degradable, such aspolylactates and other biologically derived polyesters, or polyamides orpolyesters chemically modified with hydrolyzable, oxidizable, orphotolytically unstable units or photosensitizing additives, such asbenzophenone. Such polymers may include polycaprolactam modified bycopolymerization with caprolactone, oxalate esters, or glycolides. Suchpolymers, especially when in monofilament, thin rod, or net form, willin the environment tend to develop a higher level of exposed surfaceupon leaching of the poly(vinyl alcohol) and thus degrade more rapidlyto lower molecular weight, more brittle, less form-retaining polymersupon longer exposure to the environment, such as sun, rain, lake or seawater, compost piles, trash piles, garbage dumps, and the like.

Blends of the composite with a water-soluble or water- dispersiblepolyester may be useful as powdered sizing aids for textiles, which maybe removed at the appropriate time by washing.

The composite in combination with polar polymers, with or withoutwater-soluble electrolytes, may be processed into sheet from which, withappropriate extraction techniques, the electrolytes and/or thepoly(vinyl alcohol) may be removed to leave a porous plastics sheet,useful, inter alia, in separations technology. Extracted fibers with aporous structure may also be prepared.

The composites may be blended with ethylene-vinyl alcohol copolymers andmelt-processed as adhesive resin compositions or as tie layers withimproved barrier properties for composite multi- layer bottles orpackaging.

The blends, where the polar polymer may readily form fibers, may beprocessed by melt-extrusion techniques into fibers of high waterabsorption. The blends may also be extruded and fibrillated into fibersfor uses, such as non-woven bonded materials, with high waterabsorption. Such fibers or other extrudates may be useful, especiallythose prepared with an environmentally degradable polyamide, as netting,monofilaments, components of diaper backings, ground covers, and thelike.

In the following examples, which describe the physical and mechanicalproperties of numerous blends formed from combining the melt processablePVOH/Acrylic co- and terpolymer composites with polar polymers such aspolycaprolactam, the following abbreviations are used: "Nylon" forpolyamides in general, Nylon 6 for polycaprolactam, PVOH for the one ormore specific polymers of the Example with greater than 50 mol % ofunits of vinyl alcohol, "Acrylic polymer" for the one or more particularcopolymers of an alkyl methacrylate with a vinyllactam and/or acopolymerizable acid.

EXAMPLES Examples 1-14

These examples describe blends of a poly(caprolactam) having a highamine-group end content with a composite of AIRVOL®-205 with a methylmethacrylate/N-vinylpyrrolidone copolymer. AIRVOL®-205 is a poly(vinylacetate) hydrolyzed to 88-89% vinyl alcohol of M_(w) 13-50,000.

Nylon 6(XPN) obtained from Allied Signal consisted of 64.93 and 1.07meq. of amine and acid end groups respectively. The glass temperatureTg, of the Nylon 6(XPN)/PVOH-Acrylic blends, TABLE I, exhibited amonotonic increase with increasing amount of the PVOH-Acrylic composite.A similar but reverse trend may also be observed, TABLE I, for both themelt temperature, T_(m), and heat of fusion, DH_(f). These changes inthe thermal properties of the blends are characteristic evidences ofcompatibility between the existing phases of the blends.

The blend mixture is fed into the hopper of a 1 inch (25.4 mm) singlescrew, 24 to 1 L:D, extruder in which the mixture was melt compoundedand pelletized. The processing conditions were as follows:

    ______________________________________    EXTRUDER BARREL       ZONE-1 = 210° C.    TEMPERATURE:          ZONE-2 = 210° C.                          ZONE-3 = 213° C.    EXTRUDER DIE TEMPERATURE:                          DIE-1 = 216° C.                          DIE-2 = 216° C.    EXTRUDER SCREW SPEED: = 80 RPM    ______________________________________

The pellets were dried and evaluated by DSC for thermodynamic stabilityand miscibility. As shown in TABLE I, the melt processable PVOH/Acryliccomposites were found to be exceptionally miscible and compatible withthe NYLON 6(XPN) polymer in amounts up to 70% by weight of P(MMA-NVP)acrylic copolymer. It should be noticed that all compositions of theblends containing the PVOH/Acrylic composite retained the high meltingpoint of the NYLON 6, which makes them suitable for high temperatureapplications.

In EXAMPLE 13, a binary blend, consisting of NYLON 6(XPN) and a meltprocessable composition of AIRVOL®-205 and the acrylic copolymerP(MMA-NVP=75/25) in the weight ratio of 3:2, was melt compounded,extruded and pelletized at the previously described processingconditions to yield a thermally stable blend. The thermal properties ofthe blend were evaluated by DSC and are listed in TABLE I.

                                      TABLE I    __________________________________________________________________________    Thermal Properties of Homopolymers and Blends in the System: NYLON-    205:P(MMA-NVP = 75/25) = 4:1).    No.       POLYMER/COMPOSITE                        COMP. (w/w)                                Tg (°C.)                                      Tm (°C.)                                           DHf (J/g)    __________________________________________________________________________    1. NYLON-6(XPN)     100     52.21 224.88                                           68.03    205:P(MMA-NVP =       100              68.7;114.33                                182.62                                      24.01       75/25) = 4:1    205:P(MMA-NVP =       100       75/25) = 3:2    4. EX. 1/EX. 2      95/05   51.26 222.14                                           6439    5. EX. 1/EX. 2      90/10   53.24 222.11                                           60.83    6. EX. 1/EX. 2      85/15   53.99 221.61                                           56.21    7. EX. 1/EX. 2      80/20   55.02 221.12                                           46.25    8. EX. 1/EX. 2      75/25   55.97 221.32                                           50.92    9. EX. 1/EX. 2      70/30   60.16 221.37                                           45.05    10.       EX. 1/EX. 2      60/40   63.16 219.90                                           40.39       EX. 1/EX. 2      50/50   64.38 218.91                                           35.84       EX. 1/EX. 2      40/60   69.16 215.17                                           18.97       EX. 1/EX. 2      30/70   73.47 219.65                                           15.58       EX. 1/EX. 3      50/50   60.00 215.53                                           33.61    __________________________________________________________________________

Examples 15-17

Binary blends of poly(caprolactam), Nylon 6(CAPRON 8202) M_(w) ca.18,000, having an approximately equal amount of acid and amine endgroups and a melt processable composite of AIRVOL®-205 and the acryliccopolymer P(MMA-NVP=75/25) were prepared by dry blending and meltcompounding in a single screw extruder at the processing conditionsdescribed in EXAMPLE 1. The extrudates were pelletized and dried in aforced air oven prior to thermal analysis by DSC and injection moldingon an ARBURG injection molding machine equipped with a heated ASTMfamily mold for the formation of test pieces. The molding conditionswere: Nozzle: 228° C.; Zones 1, 2, and 3: 223°-230° C.; injectionpressure 3.1 mPa; back pressure 2.1 mPa; mold temperature 35° C. Thethermal and mechanical properties are listed in TABLES II and IIIrespectively. The incorporation of the PVOH-Acrylic composite into theNylon 6 phase has little effect on the impact and tensile properties ofthe polycaprolactams.

                                      TABLE II    __________________________________________________________________________    Thermal Properties of Homopolymers and Blends in the System: Nylon    205:P(MMA-NVP = 75/25) = 4:1.    No.       POLYMER/COMPOSITE                     COMP. (w/w)                             Tg (°C.)                                  Tm (°C.)                                       DHf (J/g)    __________________________________________________________________________       Nylon 6(CAPRON 8202)                     100     54.25                                  223.96                                       70.97       EX. 15/EX. 2  90/10   52.60                                  221.99                                       70.04       EX. 15/EX. 2  80/20   54.18                                  222.33                                       61.06    __________________________________________________________________________

                  TABLE III    ______________________________________    Physical Properties of Blends in the System: Nylon 6(CAPRON    205:P(MMA-NVP = 75/25) = 4:1.                       EXAMPLES    PHYSICAL PROPERTY    15      16      17    ______________________________________    SPECIFIC GRAVITY     1.136   1.148   1.158    TENSILE-YIELD, gPa   25.8    26.1    28.5    ELONGATION @ BREAK % >200    >200    >200    TENSILE-MODULUS, mPa 1.15    1.27    1.32    TENSILE IMPACT STRENGTH                         1232.25 1072.81 628.66    (kJ/m2)    DYNATUP IMPACT STRENGTH                         54.91   74.18   6.98    (J)    NOTCHED IZOD @ 0° C. (J/m)                         0.71    0.56    0.62    NOTCHED IZOD @ 23° C. (J/m)                         1.29    1.15    1.03    UNNOTCHED IZOD @ 23° C. (J/m)                         47.48   46.79   47.70    (NO BREAK)    UNNOTCHED CHARPY (kJ/m2)                         70.80   70.92   70.21    (NO BREAK)    ROCKWELL HARDNESS    88.05   92.35   93.80    (unannealed), L    ROCKWELL HARDNESS    93.30           95.80    (ann. 4 hrs. @ 80° C.), L    DTUFL (264 psi, 2° C./min.)                         51.15   52.00   50.30    (unannealed) 0° C.    DTUFL (264 psi, 2° C./min.)                         60.20           53.55    (ann. 4 hrs. @ 80° C.), °C.    CLASH-BERG TORSIONAL    MODULUS,    gPa @ 40° C.  0.83    0.67    0.67    gPa @ 80° C.  0.34    0.28    0.23    gPa @  120° C.                         0.27    0.23    0.17    ______________________________________

Examples 18-35

These examples demonstrate the blending of the melt-processablecomposites, here based on an acrylic terpolymer, with variouspolyamides. In the following blend compositions, the acrylic compositesstudied were two:

a) PVOH-1 is a 4:1 composite of a poly(vinyl acetate) hydrolyzed to87-89% "vinyl alcohol", MW described by the supplier as 13,000-50,000,and known as AIRVOL®-205 (Air Products Co., Allentown, Pa.) with theacrylic terpolymer prepared and isolated as in European PatentApplication 91/3112652, of the composition P(MMA-NVP-MAA=70/25/05),where MMA is methyl methacrylate, NVP is N-vinyl pyrrolidone, and MAA ismethacrylic acid;

b) PVOH-2 is a 4:1 composite of fully hydrolyzed PVOH (AIRVOL®-107), MW13,000-50,000, degree of hydrolysis 98-98.8%, with an acrylic terpolymerP(MMA-NVP-MAA=70/25/05).

Samples of Nylon 6, (Example 15), Nylon 11 (polyundecanolactam), Nylon12 (polydodecanolactam) and a special grade of transparent Nylon 12,probably containing other functionality to lessen crystallinity and makethe polymer transparent, trade name Grilamid TR55FC, supplied byEMS-American Grilon Inc., Sumter, S.C., were dried in a forced air ovenat 75° C. prior to blending and melt compounding in a Killion extruderwith the previously prepared melt processable PVOH composite. For thepurpose of comparison, samples of each of the Nylon resins were alsosimilarly extruded and pelletized. The pellets derived from thecomposites and the neat resins were further processed by extrusion andinjection molding into thin films (3-5 mils) and ASTM parts. The filmswere tested for oxygen permeability while the tensile and impactproperties of the parts were evaluated by the ASTM methods.

As can be seen from the data presented in TABLES IV-VII the O₂permeability of the Nylon/PVOH-Acrylic Terpolymer blends show a 30 to50% improvement over that of the neat Nylons at 80% relative humidity.This improvement in O₂ permeability is significant particularly when itis considered that moisture has a deleterious effect on the gas barrierproperty of both Nylon and PVOH. Improvement may also be observed in thetensile properties of the various Nylon blends. However, all of theNylon/PVOH-Acrylic Terpolymer blends exhibited a loss in impactproperties. This trend in tensile and impact properties is observed forblends of Nylon with both PVOH-1 and PVOH-2. A possible explanation forthe improvement in physical properties may be the intermolecularinteraction between the --O--H of PVOH and the --N--H and --C═O moietiesof the Nylon.

Comparative Examples 18-21

Samples of Nylon 6, Nylon 11, Nylon 12 and a special grade oftransparent Nylon 12(Grilamid TR55FC) were dried in a forced air oven at75° C. and then either extruded into thin (3-5 mils) films or injectionmolded on an Arburg injection molding machine. The thin films wereextruded at the following processing conditions:

    ______________________________________    EXTRUDER BARREL     ZONE-1 = 191.0° C.    TEMPERATURE:        ZONE-2 = 204.4° C.                        ZONE-3 = 204.4° C.    DIE TEMPERATURE:    DIE-1 = 199.0° C.    RATE                RPM = 55    ROLL TEMEPERATURE:  38.0° C.    ______________________________________

The injection molding conditions for Nylon 6 and 11 were as follows:Nozzle: 234° C.; Zones 1, 2 and 3: 222, 230 and 22° C. respectively:injection pressure=3.1 mPa; back pressure=2.1 mPa; mold temperature=52°C. The molding conditions for Nylon 12 differ only in temperature fromthat of the above: Nozzle: 243° C.; Zones 1, 2 and 3: 240°, 264° and257° C. respectively. The gas permeability and mechanical properties arelisted in TABLE IV.

                                      TABLE IV    __________________________________________________________________________    Physical Properties of Nylon-6, -11, -12 and Grilamid.                               EXAMPLES    PHYSICAL PROPERTY          NYLON 6                                     NYLON-11                                           NYLON-12                                                 GRILAMID    COMPARATIVE EXAMPLES:      18    19    20    21    __________________________________________________________________________    TENSILE-YEELD, mPa         31.7  10.5  27.3  68.5    ELONGATION @ BREAK %       >260  >260  >256  >180    TENSILE-MODULUS, gPa       1.3   0.26  0.93  1.87    DYNATUP IMPACT STRENGTH (J)                               68.9  45.80 42.49 79.07    NOTCHED IZOD @ 23° C. (J/m)                               139.37                                     BUCKLE                                           46.46 18.69    DTUFL (264 psi, 2° C./min.) (unannealed) °C.                               53.55 47.05 56.95 129.05    DTUFL (264 psi, 2° C./min.) (ann. 4 hrs. @ 80° C.),    °C.                 58.50 54.20 58.20 132.45    O.sub.2 PERMEABILITY, 80% R.H    73.08 66.60 54.82    (cc. mil/100 in.sup.2 · Atm · Day)    __________________________________________________________________________

Examples 22-25

The PVOH described in EXAMPLE 4 was dry blended with the acrylicterpolymer, P(MMA-NVP-MAA=70/25/05), of molecular weight MW=77,000,extruded and pelletized to yield a melt processable PVOH composite. ThePVOH composite was combined with NYLON 6, NYLON 11, NYLON 12 andGRILAMID TR55FC to yield blends of a 4:1 ratio of NYLON to meltprocessable PVOH. The mechanical properties of the blends were evaluatedaccording to ASTM standards. A list of the properties are given in TABLEV.

                                      TABLE V    __________________________________________________________________________    Physical Properties of Blends of Nylon with Melt Processable    PVOH(AIRVOL-205)/P(MMA-NVP-MAA = 70/25/05)    EXAMPLES:                  22  23  24  25    __________________________________________________________________________    NYLON 6 % (w/w):           80    NYLON 11 % (w/w):              80    NYLON 12 % (w/w):                  80    GRILAMID % (w/w):                      80    PVOH-1 % (w/w):            20  20  20  20    PHYSICAL PROPERTY    TENSILE-YIELD, mPa         56.79                                   26.77                                       40.58                                           75.99    ELONGATION @ BREAK %       319.90                                   232.60                                       233.10                                           181.40    TENSILE-MODULUS, gPa       1.84                                   0.56                                       1.37                                           1.99    DYNATUP IMPACT STRENGTH (J)                               6.75                                   5.00                                       5.78                                           20.88    NOTCHED IZOD @ 23° C. (J/m)                               58.21                                   34.71                                       22.96                                           13.35    DTUFL (264 psi, 2° C./min.) (unannealed) °C.                               53.65                                   49.40                                       57.15                                           124.25    DTUFL (264 psi, 2° C./min.) (ann. 4 hrs. @ 80° C.),    °C.                 58.10                                   49.80                                       62.25                                           124.30    __________________________________________________________________________

Examples 26-29

The melt processable PVOH composite used in the examples (PVOH-2)consisted of AIRVOL®-107 (Mw=13-50K, and degree of hydrolysis equal to98.0-98.8 mol. %) and an acrylic terpolymer of MMA/NVP/MAA =70/25/05;the composite is described in Examples 18-35. The PVOH composite, wasmade by a process of melt compounding in a single screw extruder. Thecomposite, in the form of pellets, was combined with all of the Nylonsdescribed in EXAMPLES 18-21, except Grilamid, melt compounded, extrudedand pelletized at the following conditions:

    ______________________________________    EXTRUDER BARREL       ZONE-1 = 201° C.    TEMPERATURE:          ZONE-2 = 213° C.                          ZONE-3 = 212° C.    EXTRUDER DIE TEMPERATURE:                          DIE-1 = 206° C.                          DIE-2 = 206° C.    EXTRUDER SCREW SPEED: = 100 RPM    ______________________________________

In the case of the PVOH/Grilamid blend, the extrusion process wascarried out at higher barrel and die temperatures: ZONES-1, -2 and -3were 221°, 240° and 241° C. respectively; DIES-1, and -2 were 232° and221° C. respectively. The extrudate was fed to a water bath and apelletizer. The extruded pellets were dried in a forced air oven at 75°C. prior to injection molding on an ARBURG injection molding machine.The compositions are summarized in weight percent with their respectivemechanical properties in TABLE VI. The impact values were testedaccording to ASTM D256-84 Izod Impact Test. The Tensile Yield Strength,Elongation at Break and Tensile Modulus were tested according to ASTMD638-84. The drop weight impact was measured according to the procedureof ASTM D2444 with the Dynatup impact apparatus. The deformationtemperature under load (DTUFL) was measured at a load of 1.8 mPa indegrees centigrade using ASTM D 648-72 with 0.25 in. (6.35 mm) thicktest specimens.

                                      TABLE VI    __________________________________________________________________________    Physical Properties of Blends of Nylon with Melt Processable    PVOH(AIRVOL-107)/P(MMA-NVP-MAA = 70/25/05)    EXAMPLES:                  26  27  28  29    __________________________________________________________________________    NYLON 6 % (w/w):           80    NYLON 11 % (w/w):              80    NYLON 12 % (w/w):                  80    GRILAMID % (w/w):                      80    PVOH-2 % (w/w):            20  20  20  20    PHYSICAL PROPERTY    TENSILE-YIELD, mPa         45.52                                   10.45                                       29.78                                           69.43    ELONGATION @ BREAK %       221.67                                   175.00                                       205.00                                           164.00    TENSILE-MODULUS, gPa       1.95                                   0.44                                       1.23                                           2.37    DYNATUP IMPACT STRENGTH (J)                               10.27                                   2.88                                       9.04                                           9.27    NOTCHED IZOD @ 23° C. (J/m)                               42.17                                   57.14                                       26.17                                           21.36    DTUFL (264 psi, 2° C./min.) (unannealed) °C.                               61.00                                   49.65                                       102.45                                           127.45    DTUFL (264 psi, 2° C./min.) (ann. 4 hrs. @ 80° C.),    °C.                 79.60                                   82.60                                       72.95                                           123.35    __________________________________________________________________________

Examples 30-35

Samples of the blend compositions listed in TABLE VII were extruded intothin (3-5 mils) films and thick sheets (20-30 mils). For the film andsheet extrusion a 1 inch (25.4 mm), 24:1 L/D and 3:1 compression ratioKillion extruder was employed. The extruder was equipped with a 6 inch(0.154 meter) coat hanger type flat film die. The processing conditionswere as follows: Extruder temperature Zone-1=197° C.; Zones-2 and -3were 207° C. The screw speed was 55 rpm. The film was extruded onto achill roll maintained at 38° C. where it was drawn down to 3 rail inthickness and wound into a roll at a speed of 30 feet (9.14 meters) persecond.

The film was tested for oxygen permeability on a MOCON Ox-Tran 1000unit, manufactured by Modern Controls of Minneapolis, Minn. The filmswere mounted in the diffusion cells where they were first purged withnitrogen as a first step in establishing a base line. This was followedby exposing the upper surface of the film to an oxygen rich atmosphereand the lower surface to the carrier gas (1% H₂ in N₂). The transmissionof oxygen at steady state was monitored and detected by a nickel cadmiumfuel cell known as a Coulox Detector. The Ox-Tran 1000 unit was equippedto record the steady state flux in units of cc. mil/100 in². Atm. Day.Measurements were made at 23° C., 0 and 80% relative humidity. The ASTMtest D-3985 for oxygen permeability was used. Results of themeasurements are reported in TABLE VII.

                  TABLE VII    ______________________________________    Physical Properties of Blends of Nylon with Melt Processable    205)/P(MMA-NVP-MAA = 70/25/05)    EXAMPLES:      30     31     32   33   34   35    ______________________________________    NYLON 11 % (w/w):                   90     70    NYLON 12 % (w/w):            90   70    GRILAMID % (w/w):                      90   70    PVOH-1 % (w/w):                   10     30     10   30   10   30    PHYSICAL PROPERTY                   45.2   33.8   59.7 37.6 49.6 31.3    *O2 PERMEABILITY    80% R.H    ______________________________________     *(cc. mil/100 in.sup.2 · Atm · Day)

Examples 36-44

These examples demonstrate the modification of a polyurethane with thecomposites described earlier.

The data listed in TABLES VIII-X show evidence of some degree ofcompatibility between the polyurethane and the PVOH-Acrylic Terpolymercomposite. Each of the polyurethane/PVOH-Acrylic Terpolymer blends showimprovement in tensile and oxygen permeability properties over therespective base polyurethane resin. Both PVOH-1 and PVOH-2/polyurethaneblends, TABLES IX and X, exhibited comparable physical properties. It isinteresting to note that both Nylon and polyurethane are capable ofhydrogen bonding interaction with the PVOH-Acrylic Terpolymer via the--O--H, --C═O and --N--H moieties. The apparent improvement in thetensile and high moisture gas permeability of the Nylon and polyurethanemay have important implications in the fiber forming properties of thesepolymers.

The melt processable PVOH composites described in EXAMPLES 22 and 26were each dry blended with three different thermoplastic polyurethaneelastomers (PUE) in the weight ratio of 4:1 PUE to PVOH. The PUE used inthe experiments are composed of the reaction product of a polyisocyanate(aliphatic or aromatic) with polyester, polyether or polycaprolactonepolyols. Chain extenders such as diols and diamines may also be used inthe preparation of the PUEs. The particular PUEs used were obtained fromDow Chemical Co. under the trade name Pellethane® (polyurethane from4,4'-methylenediphenyl diisocyanate, 1,4-butanediol andpolytetramethylene glycol) and B. F. Goodrich Co. under the trade nameEstane® (polyurethane from polyester polyol base). The mixture was firstcombined in a polyethylene bag prior to being fed into a single screwextruder of L/D=24:1 and compression ratio of 3:1. The processingconditions were as follows: Extruder barrel temperature: Zones-1, -2 and-3 were 197°, 207° and 207° C. respectively; Die temperatures were 199and 201° C. The screw speed was 100 RPM. The extrudates were fed to awater bath and a pelletizer.

The pellets were dried prior to injection molding on an Arburg injectionmolding machine equipped with a heated ASTM family mold for theformation of test pieces. The molding conditions were as follows:Nozzle: 223° C.; Zones 1, 2, and 3: 236°, 247° and 226° C. respectively;injection pressure 3.1 mPa; back pressure 2.1 mPa; mold temperature 49°C. Samples of the blends and the respective homopolymers were alsoextruded into thin (3-5 mils) films and thick sheets (20-30 mils). Forthe film and sheet extrusion a 1 inch (25.4 mm.), 24:1 L/D and 3:1compression ratio Killion extruder was employed. The extruder wasequipped with a 6 inch coat hanger type flat film die. The processingconditions were as follows: Extruder temperature Zone-1=197° C.; Zones-2and -3 were 207° C. The screw speed was 55 rpm. The film was extrudedonto a chill roll maintained at 38° C. where it was drawn down to 3 milin thickness and wound into a roll at a speed of 30 feet (9.14 meters)per second.

The films were tested for oxygen permeability on a MOCON Ox-Tran 1000unit, manufactured by Modern Controls, of Minneapolis, Minn. The filmswere mounted in the diffusion cells where they were first purged withnitrogen as a first step in establishing a base line. This was followedby exposing the upper surface of the film to an oxygen rich atmosphereand the lower surface to the carrier gas (1% H₂ in N₂). The transmissionof oxygen at steady state was monitored and detected by a nickel cadmiumfuel cell known as a Coulox Detector. The Ox-Tran 1000 unit was equippedto record the steady state flux in units of cc. mil/100 in².Atm. Day.Measurements were made at 23° C., 0 and 80% relative humidity. The ASTMtest D-3985 for oxygen permeability was used.

The impact values were tested according to ASTM D256-84 Izod ImpactTest. The Tensile Yield Strength, Elongation at Break and TensileModulus were tested according to ASTM D638-84. The drop weight impactwas measured according to the procedure of ASTM D2444 with the Dynatupimpact apparatus. The deformation temperature under load (DTUFL) wasmeasured at a load of 1.8 mPa in degrees centigrade using ASTM D 648-72with 0.25 inch (6.35 mm.) thick test specimens.

                  TABLE VIII    ______________________________________    Physical Properties of Thermoplastic Polyurethane Elastomers.    COMPARATIVE EXAMPLES:                         36      37      38    ______________________________________    PELLETHANE 2363-55D % (w/w)                         100    ESTANE 58134 % (w/w)         100    ESTANE 58309-021 % (w/w)             100    PHYSICAL PROPERTY    TENSILE-YIELD, mPa   3.9     1.9     1.8    ELONGATION @ BREAK % >231.0  >260.0  >260.0    TENSILE-MODULUS, gPa 0.10    0.03    0.04    O.sub.2 PERMEABILITY 80% R.H                         96.40   246.60  222.80    cc. mil/(100 in.sup.2 · Day · Atm.)    ______________________________________

                  TABLE IX    ______________________________________    Physical Properties of Blends of Thermoplastic Polyurethane    205)-omers with Melt Processable PVOH(AIRVOL ®    Acrylic Terpolymer.    EXAMPLES:             39     40      41    ______________________________________    PELLETHANE 2363-55D % (w/w)                          80    ESTANE 58134 % (w/w)         80    ESTANE 58309-021 % (w/w)             80    PVOH-1 % (w/w)        20     20      20    PHYSICAL PROPERTY    TENSILE-YIELD, mPa    5.5    2.1     2.8    ELONGATION @ BREAK %  228.0  >260.0  >260.0    TENSILE-MODULUS, gPa  0.21   0.08    0.08    O.sub.2 PERMEABILITY 80% R.H                          90.90  191.24  183.68    cc. mil/(100 in.sup.2 · Day · Atm.)    ______________________________________

                  TABLE X    ______________________________________    Physical Properties of Blends of Thermoplastic Polyurethane    107)-omers with Melt Processable PVOH(AIRVOL ®    Acrylic Terpolymer    EXAMPLES:            42      43      44    ______________________________________    PELLETHANE 2363-55D % (w/w)                         80    ESTANE 58134 % (w/w)         80    ESTANE 58309-021 % (w/w)             80    PVOH-2 % (w/w)       20      20      20    PHYSICAL PROPERTY    TENSILE-YIELD, mPa   6.7     3.3     2.9    ELONGATION @ BREAK % 216.0   >260.0  >260.0    TENSILE-MODULUS, gPa 0.22    0.07    0.06    O.sub.2 PERMEABILITY 80% R.H                         119.60  174.07  195.44    cc. mil/(100 in.sup.2 · Day · Atm.)    ______________________________________

Examples 45-49

These examples describe modification of polyester and polycarbonate withthe composites from a poly(vinyl alcohol) and a (meth)acrylicester/copolymerizable cyclic amide/copolymerizable add terpolymer.

Comparative Examples 45-46

Samples of PET and PC were dried in a forced air oven at 100° C., andthen either extruded into thin (3-5 mils) films or pellets. The pelletswere injection molded on an Arburg injection molding machine. The thinfilms were extruded at the following processing conditions:

    ______________________________________    EXTRUDER BARREL      ZONE-1 = 238° C.    TEMPERATURE:         ZONE-2 = 253° C.                         ZONE-3 = 254° C.    DIE TEMPERATURE:     DIE-1 = 254° C.    RATE:                RPM = 55° C.    ROLL TEMPERATURE:       38° C.    ______________________________________

The injection molding conditions for both PET and PC were as follows:Nozzle temperature: 251° C.; Zones 1, 2 and 3: 238°, 279° and 271° C.respectively: Injection pressure=3.4 mPa; Back pressure=1.8 mPa; moldtemperature=27° C. The mechanical properties data are listed in TABLEXI.

The blends described in TABLE XII were prepared by melt compounding andextruding mixtures of the melt processable PVOH composites described inEXAMPLES 18-35 with PET and PC. The blends were extruded and injectionmolded into thin films and ASTM parts respectively at the conditionsspecified in EXAMPLES 45-46. The gas permeability and mechanicalproperties are listed in TABLE XII.

An examination of the data shows an increase in modulus and elongationat break and DTUFL. However, the notched and drop weight impactdecreased with the inclusion of both PVOH-1 and PVOH-2 into PET and PC.

                  TABLE XI    ______________________________________    Physical Properties of PET and PC(CD 2000).                                   PC    POLYMERS               PET     (CD 2000)    COMPARATIVE EXAMPLES   45      46    ______________________________________    PET % (w/w)            100    PC(CD 2000) % (w/w)            100    PHYSICAL PROPERTY    TENSILE-YIELD, mPa     57.99   59.30    TENSILE-MODULUS, gPa   2.28    2.22    ELONGATION @ BREAK %   235.00  89.70    DYNATUP IMPACT STRENGTH (J)                           66.20   73.34    NOTCHED IZOD @ 23° C. (J/m)                           25.63   574.58    DTUFL (264 psi, 2° C./min.)(unannealed)                           65.20   132.45    °C.    DTUFL (264 psi, 2° C./min.)(ann. 4 hrs. @                           66.15   131.30    80° C.), °C.    ______________________________________

                  TABLE XII    ______________________________________    Physical Properties of Blends of PET and PC(CD 2000) with    Melt Processable PVOH-1 and PVOH-2 Composite.    EXAMPLES:           47      48      49    ______________________________________    PET % (w/w)         80              80    PC(CD 2000) % (w/w)         80    PVOH-1 % (w/w)      20      20    PVOH-2 % (w/w)                      20    PHYSICAL PROPERTY    TENSILE-YIELD, mPa  60.40   --      60.79    TENSILE-MODULUS, gPa                        2.63    2.65    2.74    ELONGATION @ BREAK %                        213.00  1.19    >247.00    DYNATUP IMPACT STRENGTH                        3.11    1.37    5.40    (J)    NOTCHED IZOD @ 23° C. (J/m)                        14.42   10.15   19.76    DTUFL (264 psi, 2° C./min.)                        61.40   115.25  71.45    (unannealed) °C.    DTUFL (264 psi, 2° C./min.)(ann.                        65.70   113.50  71.80    4 hrs. @ 80° C.), °C.    ______________________________________

Examples 50-51

This example illustrates the physical properties of a ternary blendcontaining corn starch versus that of a binary "composite" containing anacrylic copolymer with amide and acid functionality and a poly(vinylalcohol).

In the mixing bowl of a high-intensity mixer are placed 75 partspoly(vinyl alcohol) (88% hydrolyzed, from Example 1 above), corn starch(10 parts), and 5 parts of the acrylic terpolymer(MMA/N-vinylpyrrolidone/methacrylic acid=73/25/02. A small amount (0.5%)of a hindered phenol antioxidant is also present. The granules areheated to a constant temperature of 45 ° C. at an agitation rate of800-900 rpm for 10 minutes. The free-flowing powder is collected inpolyethylene bags. A control is prepared of 85 parts PVOH and 15 partsof the acrylic terpolymer (absent the corn starch).

The above mixtures are fed to a single-screw Killion extruder where theyare melt-compounded and extruded into pellets at a screw speed of 80 rpmand zone and die temperatures of 193 ° C., except for zone 1 of theextruder, which is at 180 ° C. The pellets are dried in a forced hot airoven and then are molded on an Arburg injection molding machine equippedwith an ASTM family mold, with nozzle and zone temperatures of 200° C.,an injection pressure of 6.2 mPa and a back pressure of 1.4 mPa.

    ______________________________________                   Example 50                           Example 51    ______________________________________    Tensile Strength, mPa                     79.3      NA    Elongation at break, %                     81        NA    Tensile Modulus, gPa                     4.46      4.44    Notched Izod, J/m                     21.4      10.7    DTUFL, °C.                     62        66    ______________________________________     NA = not available

It can be seen that the ternary blend has improved notched impactproperties at the expense of a slight decrease in heat-distortiontemperature.

Example 52

In a manner similar to Example 50, a blend of 65 parts of the poly(vinylalcohol), 20 parts of corn starch, 10 parts of the acrylic tetrapolymer(MMA/N-vinylpyrrolidone/ethyl acrylate/methacrylic add=55/25/18/02, and5 parts glycerol were blended, extruded, and molded.

Example 53

This Example demonstrates that the composite of poly(vinyl alcohol) andthe acrylic co- or terpolymer has a continuous phase of poly(vinylalcohol) and a dispersed structure of the acrylic additive polymer. Ablend which is a 4:1 composite of a poly(vinyl acetate) hydrolyzed to87-89% "vinyl alcohol", MW 13,000-50,000, with the acrylic copolymer ofthe composition P(MMA-NVP-=75/25), is examined by transmission electronmicroscopy and the poly(vinyl alcohol) is shown to be the continuousphase, with the acrylic copolymer dispersed in particles of ca. 0.1micron size throughout.

Example 54

This Example demonstrates that the barrier properties of poly(vinylalcohol) are not improved by being composited with the acrylicterpolymers. Below are compared the barrier properties of unmodifiedpoly(vinyl alcohol) (as used in Example 53), the PVOH modified with theacrylic copolymer P(MMA-NVP)=75/25 in a 4:1 ratio, and with an acrylicterpolymer P(MMA-NVP-MAA)=70/25/05, again in a 4:1 ratio. Permeabilityis to oxygen, measured by a Mocon Ox-Trans 1000 unit at 23 ° C., usingthe method and conversion factors disclosed in U.S. Pat. No. 5,147,930,which are standards in the measurement of gas permeability. Permeabilityis measured in the mixed unit system of cc..mil/(100 in2.day.atm andconverted to cm³.mm/m².atm.day.

    ______________________________________                      MMA/         PERMEABILITY,          MMA/NVP =   NVP/MAA =    cc × mm/m2 ×    PVOH  75/25       75/20/5      atm × day    ______________________________________    100                            5.12    80    20                       35.4    80                20           47.2    ______________________________________

We claim:
 1. A polymeric blend comprising:(a) from about 80 to about 95parts of at least one polar polymer selected from the group consistingof poly(vinyl chloride), a polycarbonate, a polyglutarimide, a polymerof methyl methacrylate, a polyamide, a polyester, or a polymercontaining units derived from styrene and acrylonitrile, wherein the atleast one polar polymer is not of natural origin; (b) from about 5 toabout 20 parts of a polymeric composite of:i) from about 60 to about 95parts by weight of a first polymer containing at least 50 mol % of unitsof the structure ##STR11## ii) from about 5 to about 40 parts by weightof a second polymer containing at least about 70 parts of units derivedfrom at least one of a lower alkyl methacrylate or acrylate, and atleast one of either up to about 25 parts of units derived from a vinylor vinylidene monomer containing an amide group or up to about 25 partsof units derived from an unsaturated carboxylic acid or anhydride, thecomposite containing the second polymer dispersed in a continuous phaseof the first polymer.
 2. The blend of claim 1 wherein the polyamide is apolylactam, the polycarbonate is the polycarbonate formed from2,2-bis(4'-hydroxyphenyl)propane, the polyester is poly(ethyleneterephthalate), and the polymer containing units derived from styreneand acrylonitrile is an acrylonitrile/butadiene/styrene (ABS) polymer.3. The blend of claim 1 wherein the polymeric composite comprises:(a)from about 60 to about 95 parts by weight of a first polymer containingat least 50 mole % of units of the structure; ##STR12## ii) from about 5to about 40 parts by weight of a second polymer containing at leastabout 75 parts of units derived from methyl methacrylate, and at leastone of either up to about 25 parts of units derived from N-vinylpyrrolidone or up to about 25 parts of units derived from methacrylicacid.
 4. The blend of claim 1 in the form of an extruded film, extrudedsheet, extruded fiber, or injection-molded article.
 5. The blend ofclaim 1 wherein components (a), (b)(i), and (b)(ii) are combinedessentially simultaneously.